Confirmation for read email

[gratis-download.be]

Hi, I can't find the setup to get a confirmation notification when someone reads/opens the emails I've sent. Is this possible with Zimbra desktop? Or is there a delivery confirmation tool? Is this possible without inserting scripts in the email content? Because most mail programs will trigger alerts about unsafe content being included in your email. I like to know this so I can inform the Dutch speaking readers of my blog. Thanks for your help.